Serbian police officers of the Special Anti-Terrorist Unit pose for a picture in their base outside Belgrade October 8, 2014. When the killing of an unarmed black teenager by a white policeman in Ferguson, Missouri, in August sparked sometimes violent protests, the response of police in camouflage gear and armoured vehicles wielding stun grenades and assault rifles seemed more like a combat operation than a public order measure. Some U.S. police departments have recently acquired U.S. military-surplus hardware from wars abroad, but there are many law enforcers around the world whose rules of engagement also allow the use of lethal force with relatively few restrictions. But for every regulation that gives police wide scope to use firearms, there is another code that sharply limits their use. In Serbia, police may use measures ranging from batons to special vehicles, water cannon and tear gas on groups of people who have gathered illegally and are behaving in a way that is violent or could cause violence, but they may use firearms only when life is endangered. (Photo by Marko Djurica/Reuters)

The sun sets over the sea looking towards Lands End viewed from Gwenver beach near Sennen Cove on February 7, 2011 in Cornwall, England. (Photo by Matt Cardy/Getty Images)

Hindu women worship the Sun god in the polluted waters of the river Yamuna during the Hindu religious festival of Chatth Puja in New Delhi, India, November 3, 2019. (Photo by Adnan Abidi/Reuters)

Jean Pierre Augustin falls out of the ring after being hit by Chris Arreola during a Premier Boxing Champions Heavyweight Bout at AT&T Stadium on March 16, 2019 in Arlington, Texas. (Photo by Tom Pennington/Getty Images)

A series of Japanese good luck charms, called “Daruma”, are lined up ahead of the major national elections November 9, 2003 in Takasaki, Japan. The Daruma is said to bring exceptional good luck in all walks of life, but is used especially during election time by all candidates. People think that if they face a difficult situation, as symbolized by the doll that returns to its original position when knocked over, they will always bounce back. (Photo by Koichi Kamoshida/Getty Images)

Casey Stoner of Australia and Repsol Honda Team rounds the bend during the third day of MotoGP testing at Sepang Circuit on February 2, 2012 in Kuala Lumpur, Malaysia. (Photo by Mirco Lazzari gp/Getty Images)

Players of the USA celebrate in the dressing room following their team's victory in the 2019 FIFA Women's World Cup France Final match between The United States of America and The Netherlands at Stade de Lyon on July 07, 2019 in Lyon, France. (Photo by Maddie Meyer – FIFA/FIFA via Getty Images)

Engineer Mikhail Venin works on an antenna for the Express AM8 new generation geostationary telecommunications heavy satellite at the large-sized transformed mechanical systems centre of the Reshetnev Information Satellite Systems company in the Siberian town of Zheleznogorsk April 2, 2014. The Express AM6 is a new generation satellite providing services including Russian governmental and presidential mobile communication, digital television and broadcasting, according to the Reshetnev company representatives. (Photo by Ilya Naymushin/Reuters)